|Location Map ( geo)|
|Distance:||5.9 miles (9.5 km)|
|Meets:||A484, A4214, A4138, A484|
|Route outline (key)|
It has two branches: one (unnumbered on the ground) running from Llanelli town centre to join the route roughly halfway along its course at Machynys; and a second (unnumbered on many maps) starting at Morfa and providing a means of rejoining the A484 earlier, at Trostre, where the A4138 is also accessible.
The first branch, running southeast from the town centre, is part of the original route of the B4304. That started on the then-A48 and ran west along the now-pedestrianised Park Street and Stepney Street before turning south and following the current route of the B4304 over the railway line into the docks. The extension to Machynys came later, and the southern bypass no earlier than the 1990s. The spur through Trostre is the newest change to the road's route.